This invention relates to a new group of compositions that are useful in preventing nylon and wool fiber and the fabrics made from them, including carpeting and upholstering fiber, from being permanently stained by food colors contained in foods spilled on the fiber. This new group of sulfonated phenol-formaldehyde or naphthol-formaldehyde and anionic surfactant compositions not only block the stain from adhering to the fiber but also minimize any yellowing or discoloration which ultimately deteriorates the lightfastness typically caused by phenol-formaldehyde or naphthol-formaldehyde condensates.
Heretofore, fibers were treated with acid dye fixing agents, such as INTRATEX.RTM.N, to block the dyeing sites on the fiber. This type of sufonated phenol-formaldehyde condensates prevented the fibers from becoming "dyed" with the food colors, such as FD&C Red 40 in KOOL-AID.RTM.. Additionally, fluorocarbon finishes such as ZEPEL.RTM. and SCOTHCHGARD.RTM. are known to repel water-borne and oil-borne stains, and are usually applied after dyeing, unless they are built into the greige fiber. These finishes, however, do not afford a satisfactory protection against food colors, which is the reason for using Food Color Stain Blocking Agents in addition to the Fluoro-Carbon Finishes.
INTRATEX N, as many other such fixing agents, tends to slightly yellow or discolor the fiber while affecting at the same time its lightfastness. This fact alone limits the amount which can be applied to the fiber, since the amount of yellowing is in direct proportion to the percent of active ingredient exhausted onto the fiber, and this limiting amount is frequently not sufficient to produce the desired stain blocking effect.
In addition, it may be fairly obvious that products such as INTRATEX N are able to convey stain blocking properties to nylon fibers, depending on the type of fiber 6 or 66 and heat-setting history, Seussen (dry heat) Set or Superba (pressurized steam) Set, but it is also obvious that the lightfastness could be seriously impaired.
Additionally, it can be shown that nylon 6 and 66 heatset under dry and humid conditions treated with INTRATEX N type products at different concentrations, temperatures, pH, and times of treatment, reveal that nylon 66 would be the easiest to protect from a standard food color.
It has been shown that the optimum amount of INTRATEX N required to protect nylon 66 from a solution containing FDA Red 40 adjusted at a pH of 2.8-3.0 with citric acid was found to be about 1.0% for Seussen Set and 1.5-2.5% for Superba Set yarn. With nylon 6, much higher concentrations of INTRATEX N are required to achieve the same level of food color stain protection i.e. Seussen Set 2.0-3.0% and Superba Set 3.5-7.0%. Therefore, Nylon 6 Superba Set requires a much higher concentration of INTRATEX N to achieve the same kind of protection possible on nylon 66 and that this higher requirement would severely impair the lightfastness of nylon fiber treated with a stain blocking product.
Likewise, fibers have been treated with anionic surface active agents such as CENEGEN.RTM.7 . These surfactants afford little stain blocking ability to the treated fibers but cause minimal yellowing and have no deleterious effects on the lightfastness of the fibers.